This invention relates generally to portable data acquisition systems and more particularly to systems employing bar code reading devices.
It is a growing practice in many retail businesses to utilize portable data terminals to expedite the taking of inventory. Such devices are typically microprocessor based units which are housed in a relatively small case so that they can be readily held in one's hand. In order to enable desired data, e.g., the identity of a particular item, its quantity, etc., to be entered into the device for storage and subsequent use, data terminals usually include a plurality of alpha-numeric keys on the case. In addition it is typical for such data terminals to include an alpha-numeric display, e.g., LED or LCD, for displaying the data which has been entered/stored, and communication means, e.g., a modem and associated interface, for enabling the uploading/downloading of data between the terminal and some peripheral device, e.g., a host computer.
Portable data terminals of the above type are commercially available from various companies, such as Telxon Corporation, of Akron Ohio, and Hand-Held Products, Inc., of Charlotte, N.C.
In order to mechanize the input of some data, e.g., information typically contained in a bar code, such as the Universal Product Code (UPC), some data terminals include means for mounting a bar code reading device, such as a light pen or wand, thereon to form a bar code reading, data acquisition terminal. One such a hand-held data terminal is shown and described in U.S. Pat. No. 4,621,189 (Kumar et al). Mechanized entry of bar code data into such devices is accomplished by drawing the light pen portion of the terminal across a bar code. While the use of a light pen input for a portable data terminal does, in fact, speed up the data entry process, it nevertheless still leaves much to be desired from the standpoint of ease of use, e.g., a light pen or wand requires contact with the bar code to be read. That characteristic renders wands/light pens of little use in applications, e.g., warehouses, store rooms, where the bar code is located some distance away so that the wand/scanner cannot be easily brought into contact with the code to read it. Light pens/wands also suffer from other well known disadvantages.
Numerous portable or hand-held laser scanners which do not require contact with the bar code to be read have been disclosed in the patent literature and many are commercially available. Such devices obviate many of the disadvantages of light pens/wands and are typically composed of a relatively small, light weight, scanning head. The head is arranged to be held in the users hand for projecting a laser beam generated scan pattern onto a bar code at which the head is aimed. This action illuminates the bar code. The head also includes means to process the light reflected off the bar code to convert it into an electrical signal indicative of the bar codes bars and spaces. These signals are decoded either in the head or in a console unit to which the head is connected effect the "reading" of the bar code. For example, in U.S. Pat No. 4,575,625, of which I am the inventor, and which is assigned to the same assignee as this invention, there is disclosed one such hand-held laser scanner. That scanner is a completely self-contained unit in that it includes laser scanning means and power supplies, a decoding computer to provide a signal indicative of the information contained in the bar code, and communication capabilities to enable the uploading/ downloading of data to and from the scanner. Thus, the scanner includes, among other things, a laser tube and an associated optic bench assembly. The laser tube produces a laser beam which is directed to a rotating reflective polygon. The polygon is rotated by an associated motor assembly. The laser beam is swept by the rotating polygon through a predetermined arc and is directed out through a window in the housing to sweep across a bar code located opposite the window. A photo detector located within the housing receives the light reflected off of the bar code and converts that light into an electrical signal which is amplified and processed by an associated amplifier and signal processing circuitry, also located within the scanner. The scanner also includes a low voltage power supply, a microprocessor and associated circuitry, a high voltage power supply, a releasable input/output cable connector or plug, an associated input/output cable, and an on/off trigger assembly.
In my co-pending U.S. patent application Ser. No. 07/128,299, filed on Dec. 3, 1987, now U.S. Pat. No. 4,805,175, Feb. 14, 1989, entitled Ultra Compact, Hand-Held Laser Scanner, which is assigned to the same assignee as this invention, there is disclosed an even more compact hand-held scanner. That scanner basically comprises a laser tube and associated high voltage power assembly (or in an alternative embodiment a semi-conductor laser diode and associated supply and control means), beam folding and sweeping optics, a motor sub-assembly, a photo detector and associated amplification and signal processing circuit sub-assembly, a releasable input/output cable connector or plug, an associated input/output cable, and an on/off trigger assembly, all housed within an extremely compact and ergonomically designed housing. The housing includes a short snout or body portion in which a window through which the laser beam and the reflected light passes, and a supporting, hand-grip portion arranged to be held within the user's hand. The housing's construction enhances the balance point of the device by putting its center of gravity in the operator's hands so that it can be held comfortably for long periods of time without operator fatigue.
Examples of other hand-held laser scanners have been disclosed in the following patent literature: U.S. Pat. Nos. 4,387,297 (Swartz et al.), 4,409,470 (Swartz et al.), 4,460,120 (Shepard et al.), 4,607,156 (Koppenall et al.) and 4,760,248 (Swartz et al).
Some prior art hand-held scanners include on the scanning head a keyboard or other means for manually inputting of data therein. Thus, such devices serve as a bar code scanning, data acquisition system.
While prior art hand-held scanning devices may be sufficiently compact and light weight to be held in one's hand for use, nevertheless all still leave something to be desired from the standpoint of size and ability to be mounted onto a conventional data terminal to form a bar code scanning, data acquisition system. However, in my copending U.S. patent application Ser. No. 07/299,998, filed on Jan. 23, 1989, now U.S. Pat. No. 4,962,980, Oct. 16, 1990 entitled Laser Scanner Engine with Folded Beam Path, which is assigned to the same assignee as this invention and whose disclosure is incorporated by reference herein, there is disclosed and claimed a modular scanner ("engine") which is extremely compact in size and suitable for use in various types of scanning systems.